Forcing function generator employing conductive plastic

This paper describes a forcing-function generator which uses a conductive-plastic potentiometer to provide a forcing-function signal for testing servo systems and components. The unit described gives a sine-wave signal, but methods for generating a square wave or triangular wave are also discussed. A phase-measuring device is made an integral part of the function generator, and allows output versus input phase shift to be read directly from a calibrated dial.